The high-throughput sequencer represents a technology rapidly developing in recent years. Compared with the conventional Sanger sequencing, the high-throughput sequencing technology has the advantage that a large amount of sequence information may be read out. Its accuracy is not as high as the former, but the information exceeding the data sequence itself may be obtained, such as gene expression level or copy number variation, through the analysis on a large amount of data.
Today's mainstream sequencers all adopt SBS (sequencing by synthesis) methods, like Solexa/Illumina, 454, Ion Torrent, etc. These sequencers have a similar structure, and each of them consists of a fluid system, an optical system and a chip system. The sequencing reaction occurs in the chip. Their sequencing process is very similar as well, including: let the reaction solution flow into the chip for SBS reaction, and then, conduct signal acquisition and washing. Next, proceed with a new round of sequencing. This is a cyclical process. With the increase of cycles, the continuous single-base non-merged sequence information (e.g., ACTGACTG) may be tested. However, the high-throughput sequencer cannot completely eliminate sequencing errors. Sequencing errors may be caused by: occasional error or cumulative error in reaction, signal acquisition error, signal correction error, and so on. In existing sequencers, these chemical or optical or software errors may become noise, and cannot be identified at a single readout site, but can be eliminated through deep sequencing by multiple readout at different sites in the same sequence. The more accurate readout is an important development direction of high-throughput sequencing. However, the optimization on the accuracy by existing technologies is mostly concentrated on the optimization of the chemical reaction itself and subsequent image signal processing, and there is no innovation in the sequencing logic. There is a need for an improved sequencing method.